Ore-pulverizing ball-mill.



H. EGGERS.

ORE PULVERIZING BALL MlLL. APPLICATION FILED FEB. 24, 1912.

1,235,449 Patentad July 31, 1917.

2 SHEETS-SHEET FLEGGQERS.

ORE PULVEMZING BALI. HULL.

APPL-ICATlOH mm ma. 24, 19:1.

IM July 31, 191?- 2 SHEETS-$HEET 2.

ill

HENRY EGGEBS, 01 DENVER, COLORADO.

ORE-PULVERIZING BALL-MILL.

Specification of Letters Patent.

Patented July 31, 1917.

Application filed February 24, 1917. Serial No. 150,790.

T 0 all whom it may, concern:

Be it known that I, HENRY Eocene, a citizen of the United States of America, residing at the city and county of Denver and State of Colorado, have invented a new and useful ()re-Pulverizing Ball-Mill, of which the following is a specification!" M y invention relates to improvements in screening element for rotary ore-grinding ball mills; and the objects of my invention are:

First. To provide an ore-grinding ball mill that is provided with a mobile screening element.

Second. To provide an ore-grinding ball mill that is provided with a constantly shifting screening element.

Third. To provide a ore-grinding ball mill that is provided with a screening element that cannot clog up and that may assist in further pulverizing the ore in the mill that is not pulverized fine enough by the regular ore grinding large ball compartment of the mill to enter this screening element. v

I attain these objects by the mechanism illustrated in the accompany drawings, in which:

Figure 1, is a side elevationof the im'' proved ore grinding ball mill.

Fig. 2, is an end view of Fig. 1.

Fig. 3, is a vertical, longitudinal, sectional view of the same. Y

Fig. l, is a front view of one of the partition plates.

Fig. 5, is a transverse, sectional view on the line 55 of Fig. 3.

Fig. 6, is a front View of a modified form of the partitions, showing the same made in sections.

Fig. 7, is a detail sectional view showing a modification of the combined trunnion and ore inlet.

Fig. 8, is a sectional view of a modified form of the lining at the discharge end of the mill.

Similar letters of reference refer to similar parts throughout the several views.

Referring to the accompanying drawings:

The numeral 1 indicates the ore-feeding section of the lHlPllOVBd ore grinding ball mill; 2, the ore-grinding section, and 3, the ore screening and discharging hood or section. The sections 2 and 3 have registering flanges i and 5, respectively, which are secured together by bolts 6. The section 2 is also provided with a flange 7, which registers with and is bolted to the end plate or section 1, by bolts 8, the flange 7 being of slightly greater diameter than the plate 1, for a purpose to be hereinafter explained. The improved mill then comprises three sections, as shown by Fig. 3, which enable the mill to be conveniently assembled and taken down, and which permit of the most.

convenient manner of inserting and securing the screens and lining member as will be explained hereinafter.

The sections 1 and 3 are provided with relatively large hollow trunnions 9 and 10 respectively, which are mounted in bearing blocks or standards 11 and 12 respectively, which, are bolted to metal supporting plates 13 and 14 respectively, which preferably rest upon and are suitably secured to con crete piers or foundations l5.

Thus the center section has a flange at each end which joins the flanges on the inner ends of the end sections, and the flanges are all bolted together as above mentioned, the end surfaces of the flanged ends of the sections being machined to make close fitting joints between them.

The trunnions 9 and 10 are both hollow,

and the ore is fed into the trunnion 9 by is formed with an introverted annular flange 16, and before the sections 1 and 2 are bolted together, a hardenedsteel lining 17 is placed in the section 2, its rear end abuttingagainst the annular flange 16. This lining is slightly shorter than the section 2, anda hardened steel end plate 18 isinserted in the forward end of the said section and rests against the forward end of the lining, as.

shown by Fig. 3, and this plate has an axial openingof the same diameter as the ore feed inlet in the trunnion 9. The plate tition abuts against the outer end of the annular flange 16, and is preferably in the form of a single or unitary member comprising an outer ring or rimportion and a central body portion 20, that part of the plate lying between the rim and the body portion being so slotted as preferably to form a series of concentric hexagons, the ends of the bars formed by these slots being integally connected to radial bars,, which extend from the body portion to the rim. While the partition is preferably of unitary form, as shown by Fig. 4, it may also be made in sections, as shown in Fig. 6, in which figure the partition is formed of three sections, such arrangement alfording greater convenience in handling and shipping.

Opposite to the partition 19 and within the hood section 3, which is the discharge section of the mill, 1 place another partition 21, which is also in the form of a single piece disk, but which may also be made in sections, if desired. Each of these partitions is provided with lateral lugs 22 and respectively, that are positioned opposite each other on their adjoining sides and bear against each other and thus hold the said partitions apart. The partition 21 is held up against the partition 19 by wedges 2%, that lie between the inner inclined surface of the section 3, and the partition These wedges are supported and operated by bolts 25, which extend through them and through the peripheral surface of the section 3. The screen partition 21 has an axial projection 2", which extends to the entrance of the hollow outlet trunnion l0, and is provided with grooves as shown at 2 which catch the product passing out through the partition 21, and direct it into the outlet trunnion, as will be understood by reference to Fig. 3.

These partitions are preferably placed about two inches apart, although iii-desired they may be placed farther apart. Each bolt 25 carries a nut on its outer end, as shown in Fig. 5, and when the nuts are turned, the bolts are drawn upon, and the wedges 21 jam the partition 21 against the partition 19, which latter partition is thereby jammed against the annular flange 16 of the section 2 of the mill, and thus the two partitions are held rigidly within the section 3, so as to rotate with the mill, the lugs 22 and 23 defining the space between the said partitions.

Between these partitions 19 and 21, I place a body of relatively small balls, that is, balls that are small in comparison with the balls that are used in the regular ore grinding compartment of the mill, the balls in the regular grinding compartment being from about one and a half to five inches in diameter, while those used in the screening compartment between the two partitions are preferably about one-quarter to threeeighths of an inch in diameter. The screening apertures or narrow oblong slots in the partitions permit the ground ore to pass freely through them, while the interstices agree thickness of the layer will determine the mesh product that will issue from the mill.

The screening apertures or slots in the partitions preferably taper or are widest at their ends tlmtdischarge into the small ball screening element, and smallest on the large ball ore grinding compartment side of the casing. I

The space between the two partitions constitutes the screening compartment, and the small balls that are placed in the compartment constitute the screening element. i

Any suitable means may be employed to rotate the improved ball mill, but this is preferably accomplished in the following manner: to the flange 7 of the section 2 of the mill, is secured a ring form of gear wheel 26, by bolts 27. This gear wheel meshes with a pinion 28, on a shaft 29, which is mounted in bearings 30 and 31, which are bolted to the supporting bars 13 and 1-1 respectively on the pins 15. The end of the shaft 29 opposite to that which carries the pinion 28 has rigidly mounted thereon a pulley which maybe connected by a belt with a power source.

My invention contemplates broadly the use of any arrangement by which a mobile body of balls, pieces of metal, hard pebbles or other ore grinding material is confined in a compartment separate from the main ore grinding compartment by a suitable ground-ore passing partition, and also separated from the screened ore discharging outlet in the trunnion. i

The small ore screening balls which lie between the partitions 19 and 21, are preferably inserted into their compartment through apertures that are closed by threaded plugs 33, and that are preferably positioned in the circumferential wall of the casing between the two partitions, in positions to be easily opened and closed to permit-the removal of worn balls and the insertion of new ones, when desired.

In Fig. 3, the bore otthe trunnion 9 through which the ore is fed to the mill, is shown smooth, but if desired the said bore may be formed with a spiral channel or groove, which will act to positively carry the ore forward into the mill, as it feeds into the bore from the scoop 16.

In Fig. 7 is shown a modified form of feed trunnion 34, which is provided with a spiral channel 35.

The trunnion 10 of the mill is provided with a tapered, removable outlet sleeve or lining 36, which it desired inay'be formed with a spiral channel 37, as shown by Fig. 8, and the outer end of the trunnion is provided with a flared removable rim 38, which discharges the product clear of the bearing 12, and thus prevents the product from working into the said hearing.

The operation of my improved mobile screening ball ore grinding mill is as follows:

Having started the mill to running at a proper speed, the ore, which is first broken up in rock breakers, is fed from the scoop 16 into the mill, and is subjected to the grinding actionol' the large balls therein, which, with the small screening balls in the screening compartment of the mill, are continuously rolling over and lover as the mill rotates.

This continued rotating action of the mill keeps the large and small balls rolling over and over each other, and in the main grinding compartment of the mill the ore is ground to a powder. This ground powdered ore in the main compartment of the mill gradually feeds through the slots in the partition 1%), into the screening compartment containing the small balls, which is the final screen of the mill, and the ore in order to pass through these small balls will have been reduced to the desired mesh.

The mobile screening compartment of the mill operates to thoroughly screen the ore, and at the same time keep it constantly moving, and moreover, acts to regrind it to a more even product, which is a matter of value and an advantage where an evenly ground product is required, as in flotation and cyanid processes, and in particular the body of small balls as the mill rotates roll over and over each other through the mass of ore and keep the whole mass moving among the body of balls, and the reground thoroughly screened product as it works through them, enters the slots of the second partition and passes through them and dis charges through the trunnion at the discharge end of the mill.

And while I have illustrated the preferred construction and arrangement of my mill, 1 do not Wish to be limited to it, as many changes might be made without departing from the spirit of my invention.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In an ore pnlverizin ball mill of the character described. a horizontal cylindrical rotatable ballholding casing having an introverted annular tlange'atone end. a suitable metal lining in said casing which abuts at one end against said annular flange, a wear plate in the opposite end of said casing which abuts against the adjacent end of said lining, a cap secured to theend of said casing adjoining said plate having av hollow axial trunnion which forms the inlet to said casing, said wear plate having an aperture registering with said inlet, a hood bolted to the opposite end of the casing having an axial trunnion which forms an outlet, a pair of spaced screen partitions in said hood, the inner one abutting against said annular flange, and means *arried by the hood for jamming the outer screen against the inner screen and thereby jamming the inner screen against said flange, the space between said screens being for the reception of small hard metal balls, bearings for said trunnions and means for rotating said mill.

2. An ore pulverizing ball mill of the character described, comprising av ball-holding chamber having an annular abutment at one end, a hood section secured to the abutment end of the casing having an axial outlet in the form of a trunnion, a cap on the opposite end of the casing having an inlet in the form of a hollow trunnion and bearings for said trunnions, a. pair of spaced screen partitions in said hood section and abutting lugs on said partitions for defining the space between them, the inner partition bearing against the annular abutment on said casing, radially disposed wedges interposed between the outer partition and the end wall of the hood, the said wall being slightly dished as shown, and bolts extending through said wedges and through the peripheral wall of the hood and provided with nuts on their outer ends, the space between the partitions being for the reception of small hard metal balls, and means for rotating the casin 3. In an ore pulverizing ball mill of the character described, the combination with a lined horizontally disposed ball-holding grinding casing having a hollow trunnion, of a hood section bolted to the opposite end of the casing, having a hollow trunnion, bearings for said trunnions, and means for rotating said mill, a pair of spaced screen partitions in said hood, the outer partition having a grooved projection extending to the entrance of the adjacent hollow trunnion, the space between said partitions being for the reception of small hard metal balls, and means for rotating said mill.

:l. In an ore pulverizing ball mill of the character described, the combination with a ball-holding grinding chamber having an inlet, of a hood secured to one end of said chamber having an outlet. :1 pair of spaced partitions in said hood, each having a plurality of concentrically arranged slots extending through them, the space between said partitions being partially tilled with small hard metal balls, threaded apertures being formed in said hood coinciding with the space between said partitions, threaded plugs in said apertures, and means for rotating said mill.

5. In an orc pulverizing ball mill, the combination with a ball-holding grinding chamber having an inlet at one end and an introvereed flange at the f ner end, 01 e hood secured to the latter end of said enem- 1381, having an outiet, a pair 0f spaced partitions in said hood one of which ebuzs against the said introverted flange, each of said partitions having a piuiaiity 0% coneenti'ically arranged slots extending ihi'ough them, means connected with the heed for clamping saici'partitiens against said flan the space between said partitions being the recepsien of small hard me fini bails,

hood. being provided with plugged bailadmi'iting aperi-ui'es coinciding with the space between said partitions, anci means f0? rotating said mill.

in testimony whereof I affix my signature in presence 0i" two Witnesses.

HENRY 'ii itnesees 2 Senennn ELLIGIT, Annmn M. -1 ownn, 

